This might work if you already have a network, but otherwise good luck getting through to people on the phone.
HR will answer the generic questions, but tell you to apply online. Cold "calling" people on LinkedIn is a shot in the dark. Some people don't mind you doing it, most will ignore you.
You can start building a network by reaching out to alumni, former colleagues, open-source contributors for projects you're contributing to [1], etc.
Hardly ideal, but it's a start.
[1] And if you're not contributing to an open-source project, please do it, it's a great way to learn stuff, improve your CV, network and of course give back.
I find this kind of advice underspecified. The people struggling the most to find work are juniors: what projects are big enough that the applicant would a) know and care about them and b) get a benefit out of the network but also c) have fruit low enough for a solo junior to reach?
I tried this way-back-when and ended up submitting fixes to projects that were open source but had no real path to accepting patches from people outside the cathedral.
If you just graduated college or have no network, you can reach out to alumni and mention that connection. Or, you can ask personal friends/family for contacts (will probably be local companies, which may be a first step job).
Or you can reach out over social media. "Hi there, I follow you on X and am just getting started in the industry. Do you mind if I ask a few research questions?" A friend of mine just used this technique to land a role in an industry where he had no contacts.
If the situation is "good luck getting through to people on the phone", then that probably means this person is not a real friend of yours, they are a stranger, and you shouldn't try. You should be reaching out to people who actually know your name, or you have a mutual friend.
